martin



Aug. 20, 1946. 4 s. MARTIN I I 2,406,088

v HEAT REGULATOR Filed Dec. 6, 1941 2 Sheets-Sheet 1 Patented Aug. 20, 1946 UNI-TED STATES PATENT HEAT REGULATOR Perry S. Martin, Harrisonburg, Va, 7 3 I y I Application December 6; 1941 Serial No; 422,01 1 1 i I This invention relates: to draft regulating devices and has for its-principal object the provi sion of a simple and efficient regulator for use with space heaters burning solid fuel.

A further object of the present invention is to provide a regulator for wood and coal burning stoves of a type which will: keep the fire in the stove for a long period of time and meanwhile will hold the heat of the room at a constant degree within a small margin; 1

A still further object of the present invention is the provision'of a regulator for .a coal or'a wood burning" stove: which will respond almost entirely t'o the temperature of the room when therooml is at the normal temperature desired and which will to some: extent respond to the heat of. the stove should the room temperature be below normal, thus giving an anticipating action to the control.v

Other objects of the. invention relate primarily to details and are more specifically set forth in the claims.

With the present day electric thermostatic" controls there islno difiiculty' of any kind in; maintaininga room: at a closely regulated degree and this is still more true'where the fuel: is-liquid'or gaseous. There'are, however, many dwellings in. Which electrical-1y controlled devicescannot be used", and: still many others inwhich the cost would: beprohibitive 'even. were the electricity available. The" present? regulator is adapted for use with'either; acoal burning or a wood burning stove": 1

In'the drawings:- v Figure 1 is 'a'central section through one form ofmy device; c

Figure 2' is a rear view with the rear panel of'the mirror bafile removed.

Figure 3 is a perspective illustrating aportion of the regulator with the casingremoved.

Figure 4i is a detail illustrating the knife edge bearing of the regulating 1ever.

Figure 5 shows th device applied to a coal burning circulating heater.

Referring particularly to Figure l, the stove illustrated is of the woo-d burning type and is designated generally by the numeral. HI. It has a sheet steel wall ll, afianged b'aflle l2. and an. opening M of the. intake. of air. Secured around this opening Mby bolts extending throughthe baflie is a casting l6 which is usually especially both. The. major parts-of .thewregulatorare the;

8 Claims. (erase-e5) draft tube l8, the frame work orchassis l9 supporting the thermostat ZOandthe casing 2 l.

The draft tube IB- is square in vertical cross section, snugly fitting the casting l6 and being bolted thereto as at 23', by means of a pairtof brackets 24 spot welded to the end of the draft tube. The rear of' the draft tube slopes atari angle of about 45 providing a large 0Denil'1g"2-5 which is closed by the main damper zii pivoted on: rod: 2-! extending thru the sidewalls tothe draft vtube andbeing held against side toside movement by the two? walls of the casing 21; A pilot valve 39 is loosely pivoted to the main damper" 26, as at 3l:, and carries a zigzag member 33 serving a dual function, to limit the opening of the pilotvalve 30 and to afford attachment for thecon'trol-ling chain 34' which not only pulls the: pilot valve closed, but preceding this act, pulls the main. damper'shut. The upper surface of the pilotdamper is much larger than the opening 36 'through-themain damper so the resistance to closing of. the ilot damper is greater than the resistance to turning of the main damper 26:.- on its axis 21. This pilot damper therefore opens first and closeslast, in this way avoidinga ttooabrupt'opening or closing of the draft. v 1

Theprincipal element of the chassis is'a channel membenthewelr of? which is bent at right. angles at 31 to form a. vertical portion 38 and a horizontal portion 39. The flanges 40 of this member are necessarily severed near the bend 31.

' passageway and the portion. 39 forms. the floor'of a communicatinghorizontal passageway. Triang plate has a T-slot' atiits free end, thestem ofthe" slot bearing. the numeral. 41' an d the longer reach of the slot being numbered 48. lever 59' has a. T-head which rests on the-sloping portion. of the plate: 45, thus forming-a pairL of knife edges 51' which' materiallyadds to the chiciency and ease of controlxof the regulator To the bottom of the leveriesecured a strap 5 carrying @a'tits lower end the chain 34. p 1 Referring; particularly to; Figure 3; two small The baflle 38 forms one wall of .a vertical The regulating 4 ,to the draft tube.

Zigzag bearing members 55 are secured'to the flange 48, of the horizontal web of the channel member and in these bearing-pieces is mounted a pivot rod 56, endwise movement of which is pre-v vented by engagement with the flanges 48. A

quite heavy cam lever 68 is secured to the pivot rod 56and bears at the end 6| of its horizontal arm on a cam 82 secured to a vertical post 83 passing through theweb' 39, the plate 45 and the top casing'member 44. This post 63, preferably permanently attached to the cam, carries-amanual knob 64 turning about a dial 65 which may,

4 r J 7 formed by engagement of the damper withthe lower end of the strap 54. Under such circum stances air enters through the large space 83 between the edge of the draft tub and the casing and also through the holes 12 in the casing. This air thus flowsfrom right to left in Figure 1, un-

der the open damper entering the stove through.

the casting l6 and the opening [4.

At the same time there is a slow movement of air from between the reflecting bafile face 18 and j the wall II of the stove and also inside of the be marked in arbitrary numerals andwith arrows showing warmer in one direction and cooler in the other. V l

At its lower. free end the as at 86 to receivethe threaded end of the thermo-,

cam lever 68 is tapped stat unit 28, preferably consisting of a plurality of corrugated wafers and having a stud 61 to engage a rounded elevation 68 on the regulating le ver. i Y I The major portion of the casing 2| is a single sheet bent like a square U,"thus forming the back and the two sides of the regulator. .The casing has a'plurality of horizontalslots or openings 18 somewhat above the center and has opposed ver; tical openings. H above the draft damper when closed; and also'has a number of similar slots or openings 12 in the rearwall which is otherwise closed. The openings "provide for entry of air The openings H allow entry. of additional air and primarily afford a view of the draft damper. Th

slots in the top of the casing are optional but are foundto be quite convenient in affording a more-surejfiow-of air under certain conditions.

A channel shaped heat baflle TI is secured to the flanges 48 of the vertical web 38 of the channel member and also tothe triangular'stiffening pieces M.

The front wall 18 of this member is chromium plated soas to be heat reflecting, while the inside of this sheet is of the normal dull finish of the steelsheet. A similar piece of chromium plated steel is attached centrally within the wall, the portion 82; andthe bottom wall, the integral portion 8| of the sheet 88. The two side Walls of thisspace are formed by the two parallel walls of the outer casing, but these are large:- ly removed'in this area by the cutting of the slots 18 at both sides. The purpose of this space 85 'is to prevent heat from passing from the stove to the thermostat 28. The reflecting surface 18 likewise aids. in this feature, as does the web 38. These several members are heated by the radiant heat'from the stove and were it not for this ven tilated insulating space 85 which cools the surrounding metal, a much greater quantity of heat would be conducted through the metal to the thermostat. vI may heat insulate the thermostat from the cam lever 68 by a small fibre washer 84, but in practice do not findthis necessary.

The operation of the device is as follows:

The knob 84 is moved to select the chosen heat to be maintained, which action it will be. noted raises or lowers the upper end 6! of the lever 68 with consequent increased movement of the anchoredv end of the thermostat. Assuming the room to be. colder than desired, the main damper 26 is wide open, that ishorizontal, the stop being Theopenings l8 allow ,venti lation of an insulating space, later to be described.

bafile 11. The latter air passes in part through the open end '8'! of the reflecting bafile, partly through the optional opening"! in top of the casing and partly from left to right, in Figure 1, between the web 39 and the upper sheet 44 of the casing, thence downwardly inside of the rear wall 2| of the casing thus passing across the the heat increased too fast, even though'the room 7 were still cold? Radiant heat fromthe heated wall liof the stove passes through the optional openings 88 in the web 38 and this helps to heat the thermostat. Theelement 98 is alight'aluminum baflie adapted to prevent the passage of this radiant heat when the damper is entirely closed.

As the temperature of the stove increases the. thermostat expands. Since the screw-carrying anchored end is fixed in space by thepositioning of the lever 68, such expansion of the thermostat causes-an increased pressure on the ridge'BB of the regulating'lever 58' which turns on itsknife edge bearings 51 and pulls on the chain 34. The angle of pull plus the weight'of the pilot 38 causes a movement of the entire mass pivoted at 21 in-;

cluding the counter-weight 83 and this movement continues as lOl'lg as the thermostat is expanding; that is, until such time as the main draft damper 26 is entirely closed. 'Ilhe pilot damper is now fully open and an appreciable amount of further expansion of the thermostat is required I When the heat requirements have thus been met, thereis nomovement of air from left to.

right in the upper air passageway of the regula-- tor,that is, between the .web 38 and the top wall 44, such heat as may rise passing freely through the openings 14 and 81. There is, how- .ever, a movement of room temperature air from the bottom opening 83 upwardly'past the thermo-.

- statand from right to left in the upper horizontal space above the channel member. Since the metal of the regulator is slightly warmer than the'room temperature, this current of air passes out, through the openings 14 and 81. As the dampers 2'6 and 38 are now entirely closed, they also are at a temperature above that of the room.

Air follows the heated slopingsurface of this 86 by an appropriate casting 89.

metal and passes out through the opening 81 through the two or more holes 88 in the channel member. The thermostat is quite near the opening 83 so it is bathed almost exclusively in air at the temperature of the roomand radiation of heat from the stove is blocked by the reflecting surface 18, the vertical wall of the flanged channel member l9, the ventilated insulating space 85 and the reflecting surface 82. As a consequence, the thermostat at such times is substantially exclusively under control by the room air and responds very quickly to any change in temperature. It will be noted that the bosses 90 provide an air space between the casing and the draft tube and chassis, also that the sheet 80 makes a fairlysnug fit with the casing, being wider than the channel member l9.

When used with a coal burning stove as in Figure 5, the regulator is secured to the ash pit The slot 9| in the mirror baffie 11 is provided to receive the casing 92 of the circulating heater so as to position this baffle in the space between the stove and its light metal casing. The operation of the regulator when used with a circulating heater is substantially the same as has previously been described.

What I claim is:

1. In a draftregulator for solid fuel burning space heaters, a horizontal draft tube, a draft damper controlling the flow of air therethrough to the heater, a vertical baffle-above the draft tube, a reflector cooperating with the vertical baflie to form a vertical passageway adjacent the heater, walls forming a second vertical air passage spaced from the previously mentioned passageway, walls forming a horizontal air passage communicating with the upper ends of the two vertical passageways, a thermostat within the second passageway, and a sloping wall directing heated air from the spaced passage to a point just above the draft tube, whereby when the damper is open heated air will pass upwardly between the baflie and the reflector and thence downwardly past the thermostat, thus making the thermostat more responsive to changes in the heater temperature when the damper is open and the room is cool than it would be if the heated air were not thus circulated.

2. In a regulator for a solid fuel burning space heater, walls forming a heat insulating space ventilated to the room to be heated, additional wall cooperating with said walls to form an air passage completely encircling said space and having a hot air entrance, a hot air exit near the heater and a room air inlet further from the heater, a thermostat in said passage abov the room air inlet, adjacent said heat insulating space and distant from the hot air outlet, and means governed by the thermostat for controlling the flow of combustion air to the heater from said room air inlet whereby when said means nearly shuts ofi air to the heater, a flow of cold air will be induced in said air passage from the room air inlet past the thermostat to the hot air outlet, thereby making the thermostat responsive to room temperaure almost exclusively when the heat requirements of the room are substantially met.

3. The device of claim 2 in which the air passage includes three parallel bafiles between the thermostat and the space heater at least one of the walls being of a reflecting surface.

4. In a, draft regulator for space heaters of the type burning solid fuel, a damper for controlling the admission of air to the stove, walls forming a vertical passageway conducting heated air from the stove upwardly, walls forming a second vertical passageway, a thermostat within said'sec- 0nd passageway and operatively connected to the damper to increase or diminish the flow of air to ways to a temperature only slightly above that V of the room.

In a regulator for a solid fuel burning heater, a damper for controlling the admission of main combustion air to the heater, a thermostat operating said damper, and a series of walls between th heater and the thermostat for shielding the thermostat from radiant heat from the heater, said walls providing a portion of the boundary of an air passageway, alternately di-, recting room temperature air and heater warmed air to the thermostat as the damper is opened and closed, a plurality of said walls having heat reflecting surfaces facing in the direction of the heater.

6. The device of claim 5 in which at least one of said walls is a wall of a ventilated heat insulating space substantially at the level of the thermostat.

'7. In a regulator for a heater, a metal framework, a thermostat adjustably carried by said framework, means controlled by the thermostat for regulating the heater, a casing surrounding the framework on three sides, and projection on said frame-work for holding the casing in spaced relation to the frame-work in order to provide an insulating air space between the casing and the frame-work, whereby to shield the thermostat from heat from said heater passing through the casing walls.

8. In a heat regulator for a room heating stove, a pair of vertical walls, a sloping wall joining said walls to form three sides of a heat insulating space of which the sloping wall is the bottom, a thermostat mounted adjacent one of said vertical walls, means controlled by said thermostat for regulating the stove, and means including said sloping wall for directing air heated by the stove downwardly past the thermostat and toward the vertical wall further from the thermostat, said heat insulating space being open to room temperature and located between the stove and. the thermostat.

PERRY S. MARTIN. 

